Secondary refrigerating apparatus



Dec. 23, 1947. M. KALISCHER SECONDARY REFRIGERATING APPARATUS 2 Sheets-Sheet 1 Filed May 25, 1945 R r E m 5 T U m A VK m N O T Y L B M ATTORN EY Dec. 23, 1947. sc 2,433,188

SECONDARY REFRIGERATING APPARATUS Filed May 25, 1945 2 Sheets-Sheet 2 FIG-L3;

INVENTOR MILTON KALISCHER 7 WWW ATTORNEY WITNESSES:

Patented D86- 23,

SECONDARY REFRIGERATING APPARATUS Milton Kalischer, Longmeadow, Mass, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 25, 1945, Serial No. 595,846

9 Claims. 1

This invention relates to refrigerating apparatus comprising a secondary volatile refrigerant circuit and more especially to a means for controlling the secondary circuit.

Modern domestic refrigerators provide a compartment for storing frozen foods and a second compartment for ordinary refrigerated storage. Each of these compartments is preferably maintained at a constant temperature in spite of variations in the room temperature.

It is, accordingly, an object of this invention to provide novel and simple means for maintaining two refrigerated compartments at different but relatively constant temperatures in spite of variations in the room temperature in which the compartments are located.

A further object of the invention is to provide novel means for controlling a secondary volatile refrigerant circuit to provide predetermined temperatures in a chamber in response to changes in the ambient temperature of the chamber.

These and other objects are effected by the invention as will be apparent from thefollowing description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. 1 is a vertical section of a mechanically cooled refrigerator embodying the invention;

Fig. 2 is a front elevation of the food storage chamber of the refrigerator with the door open; and

Fig. 3 is a sectional view of the machine compartment of a refrigerator showing a modification of the invention.

Referring now to the drawings for a detailed description of the invention, the reference numeral i designates a refrigerator cabinet having an insulated food chamber H in the upper portion thereof and a machinery chamber l2 below the food storage chamber. A partition l3 divides the food chamber into two compartments, the upper compartment It being devoted to the storage of frozen foods and maintained at a temperature of about 5 F. and the lower compartment l5 being devoted to the storage of comestibles at about 40 F.

The upper compartment I4 is refrigerated by a mechanical refrigerating apparatus which hereafter will be designated as the primary apparatus. It comprises a primary evaporator l6 which is supplied through a capillary tube IS with a volatile liquid refrigerant and the refrigerant vapor is withdrawn from the evaporator l6 by a suction tube 20. The suction tube 20 connects with a sealed housing 22 containing a refrigerator compressor and a motor for driving the same. The motor and the compressor are not shown in the drawings. Compressed refrigerant is conducted from the compressor to a primary condenser 24 through a tube 26. The lower end of the condenser 24 connects with the capillary tube 18.

A motor-driven fan 28 draws air from the room over the sealed casing 22 and forces the air through the condenser 24 to cool both the casing 22 and the condenser. The temperature of the primary evaporator I6 is controlled by a thermostat 30 shown diagrammatically in the drawings. The thermostat 30 comprises a bulb 32 containing a volatile liquid, the vapor pressure of which is conducted to a metal bellows 34 which actuates a switch 36. The switch 36 controls the operation of the motor in the sealed casing 22. A permanent magnet 38,'associated with the switch 36, provides a snap-acting opening and closing movement to the switch 36 and is adjusted so that the switch 36 opens when the evaporator I6 is cooled to a predetermined temperature and closes when the evaporator l6 warms up to another predetermined temperature. The thermostat 30 thus provides that the evaporator i6 is maintained between predetermined temperature limits so that its average temperature remains constant in spite of variations in the temperature of the room in which the cabinet i0 is located. The foods stored in the compartment ll will be at a substantially constant temperature because of the thermal storage capacity of the foods.

The lower compartment I5 is cooled by a volatile refrigerant circuit 40 which hereafter will be referred to as the secondary refrigerant circuit. The secondary refrigerant circuit 40 comprises a secondary evaporator 42 consisting of a tube 44 located in heat exchange relationship with the inner metal shell 46 of the food storage chamber II. The secondary refrigerant circuit 40 also comprises a secondary condenser 48 comprising a tube 50 located in heat exchange relationship with the evaporator IS. The tubes 44 and 50 are interconnected.

The refrigerating apparatus, as thus far described, is well known in the art but has the disadvantage that the temperature of the lower compartment l5 varies with the temperature of the room in which the refrigerator is located. The refrigerator of this invention corrects this defect by rendering the secondary refrigerant system less effective when the room temperature is low than when it is high by varying the quanacsaraa tity of refrigerant which circulates in the secondary circuit.

The refrigerator comprises a chamber 52 lo- I cated in heat exchange relationship with the air of the room in which the refrigerator is situated and in Figs. 1 and 2 is shown as located in the machinery chamber i2 and in the path of the air drawn into the machine chamber by the fan 25. The chamber 52 connects through a tube 54 to the tube 44 of the secondary evaporator 42,

The chamber 52 contains a material 68 which absorbs some or all of the refrigerant in the secondary circuit and which is more effective in absorbing the refrigerant at low temperatures than at high temperatures. The absorbing material 56 is chosen with regard to the refrigerant in the secondary circuit 40. Thus, if the refrigerant is ammonia, the absorbing material may be water or lithium chloride, and if the refrigerant is dichlorodifluoromethane (F -I2), the absorbing material may be mineral oil.

It will be apparent that as the ambient temperature of the refrigerator decreases, more of the refrigerant of the secondary circuit will be absorbed by the material 55 so that the quantity remaining in the secondary circuit 40 is unable to transfer as much heat from the lower compartment 15 to the primary evaporator I5 as formerly. When the temperature of the ambient air of the cabinet i rises, the temperature of the material 56 will also rise and its refrigerant absorbing capacity decreases. More refrigerant will then be forced into the secondary circuit 40 so that its heat transferring action increases.

For given temperatures of the secondary condenser 48 and of the absorbing material 56, the higher the proportion of absorbing material 55 to the refrigerant of the secondary circuit 40, the less refrigerant will be available for a heat transfer between the secondary evaporator 42 and the secondary condenser 48. If this proportion is high enough, no refrigerant at all will be available for this heat transfer. For effective regulation of the secondary circuit 40, therefore, the proportion of absorbing material 55 to refrigerant should not be so high that all of the refrigerant of the secondary circuit 40 is absorbed throughout the temperature ranges at which the secondary condenser 48 and the absorbing material 55 is operated.

The ratio of absorbin material 56 to the refrigerant in the secondary circuit 40 and to the heat leakage of the lower compartment I is preferably so proportioned that the temperature of the compartment i5 remains constant in varying room temperatures. However, it may also be proportioned to vary the temperature of the compartment l5 with changes in the ambient temperature of the refrigerator. Thus the temperature of the compartment i5 can be made to rise or to fall in response to a rise in the ambient tempearture.

A modification of the invention is shown in Fig. 3. In this modification the tube is wrapped around the chamber 52 so that ;the heat of the refrigerant vapor, when compressed by the compressor, is transmitted to the absorbing material 56. In this modification less absorbing material 56 will be required than in the first-described modification because the variations in the temperature of the material will be more violent than the changes in the temperature of the ambient air of the refrigerator. This is caused by the fact that as the temperature of the ambient air rises, the heat leakage into the cabinet ii} will 4 increase and the primary refrigerating apparatus will run more frequently and/or for longer periods of time. As a result, the temperature of the refrigerant vapor in tube II will rise in a greater ratio than the rise in temperature of the ambient air and the temperature rise in the material 55 will be greater than the first-described modification. In the modification of Fig. 3, the temperature of the material 55 will also be effected by the heat load occasioned by placing warm foods in the lower compartment I! so that the effectiveness of the secondary circuit 40 is increased also when the heat load due to warm foods increases.

This aids further in holding the temperature of the food storage compartment II constant.

It will be apparent from the above that this invention provides a simple means for maintaining two refrigerating compartments at diiferent but relatively constant temperatures in varying room temperatures. It also provides a novel means for controlling a secondary volatile refrigerant circuit without introducing valves or other movable parts in the circuit.

While the invention has been shown in several forms, it will be obvious to those skilled is the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In a refrigerator having a heat-insulated chamber, a cooling means, a volatile refrigerant circuit including an evaporator for cooling said chamber and a condenser in heat-transfer relationship with said cooling means, the combination with said refrigerator of means responsive to the ambient temperature of the chamber for increasing the heat-transferring effectiveness of said refrigerant circuit when said temperature increases and for decreasing said effectiveness when said temperature decreases.

2. In a refrigerator having a heat-insulated chamber, a cooling means, and a circuit for transferring heat from the chamber to said cooling means, said circuit containing a volatile refrigerant and comprising a refrigerant condenser in heat-transfer relationship with said cooling means, an evaporator in heat-transfer relationship with said chamber, a vessel responsive to the ambient temperature of the chamber, and material in said vessel for absorbing said refrigerant, said material having a greater capacity for absorbing said refrigerant at low than at high temperatures of said material, said refrigerant and said absorbing material being in such proportion that the heat-transfer capacity of said circuit is less at low ambient temperatures than at high ambient temperatures.

3. In a refrigerator having a heat-insulated chamber, a primary evaporator, and refrigerant compressing and condensing apparatus for withdrawing vaporized refrigerant from said evaporator, compressing said vapor, and supplying the condensed refrigerant to said primary evaporator, the combination with said refrigerator of a secondary circuit for transferring heat from said chamber to said primary evaporator, said circuit containing a secondary volatile refrigerant and comprising a secondary refrigerant condenser in heat-transfer relationship with said primary evaporator, a secondary evaporator 'in heattransfer relationship with said chamber, a vessel responsive to the temperature of the refrigerant vapor compressed by said compressing apparatus, and material in said vessel, said material having a greater capacity for absorbing said secondary refrigerant at low than at high temperatures of said material, the quantity of refrigerant in said circuit being such that changes in the temperature of said compressed refrigerant vapor changes the heat-transferring effectiveness of said secondary circuit.

4. In a refrigerator having a heat-insulated chamber, a primary cooling means for directly cooling a portion of said chamber to a constant average temperature, and a secondary volatile refrigerant circuit for transferring heat from another portion of said chamber to said cooling means, said circuit including an evaporator for cooling said other portion of said chamber, a condenser in heat-transfer relationship with said cooling means, and a volatile refrigerant, the combination with said refrigerator of means responsive to the ambient temperature of the chamber for increasing the heat-transferring effectiveness of said secondary circuit when said temperature increases and for decreasing said el'ectiveness when said temperature decreases, said means being devoid of mechanical parts adapted for cooperative movement with respect to one another.

5. In a refrigerator having a heat-insulated chamber, a primary cooling means for directly cooling a portion of said chamber to a constant average temperature, a secondary volatile refrigerant circuit for transferring heat from another portion of said chamber to said cooling means, said circuit including an evaporator for cooling said other portion of said chamber, a condenser in heat-transfer relationship with said cooling means, and a volatile refrigerant, the combination with said refrigerator of means responsive to the ambient temperature of the chamber for increasing the quantity of the refrigerant in said secondary circuit when said temperature increases to render said circuit more effective and for decreasing said quantity when said temperature decreases to render said circuit less effective, said means being devoid of mechanical parts adapted for cooperative movement with respect to one another.

6. In a refrigerator having a heat-insulated chamber, a partition in said chamber dividing the same into two compartments, and a cooling means maintained at substantially constant temperature in one of said compartments to cool the same, the combination with said refrigerator of a circuit for transferring heat from the other compartment to said cooling means, said circuit containing a volatile refrigerant and comprising a refrigerant condenser in heat-transfer relationship with said cooling means, an evaporator in heat-transfer relationship with said other compartment, a vessel responsive to the ambient temperature of the chamber, and refrigerant absorblng material in said vessel, said material having a greater capacity for absorbing said refrigerant at low than at high temperatures of said material, the quantities of refrigerant and absorbing material in said circuit being such that the heat-transfer capacity of said circuit is less at low ambient air temperatures than at high ambient air temperatures.

7. In a refrigerator having a heat-insulated chamber, a primary cooling means for cooling a portion of said chamber, a secondary refrigerant system including a volatile refrigerant, a condenser for said refrigerant, said condenser being in heat-transfer relationship with said cooling unit and an evaporator for said refrigerant, said evaporator cooling another portion of the interior of said chamber, the combination with said refrigerator of means responsive to the heat load on said cooling unit for increasing the quantity of refrigerant circulating in said secondary system when said heat load increases and for decreasing said quantity when said heat load decreases, said decrease renderin said evaporator less effective, said means being devoid of parts adapted for cooperative mechanical movement with respect to one another.

8. In a refrigerator having a heat-insulated chamber, a primary evaporator associated with said chamber, a refrigerant compressing and condensing apparatus for withdrawing vaporized refrigerant from said evaporator and supplying the same with refrigerant liquid, and a secondary volatile refrigerant circuit including a, secondary condenser in heat-transfer relation with said primary evaporator, a secondary evaporator for cooling at least a portion of said chamber, and a quantity of volatile refrigerant in said secondary system, the combination with said refrigerator of means responsive to the temperature of said refrigerant condensing apparatus to increase the quantity of refrigerant circulating in said secondary circuit when the temperature of said apparatus increases and to decrease said quantity when said temperature decreases, the quantity of refrigerant in said system being such that said increase and decrease respectively increases and decreases the effectiveness of the secondary evaporator.

9. In a refrigerator having a heat-insulated chamber, a primary evaporator associated with said chamber, a refrigerant compressing and condensing apparatus for withdrawing vaporized refrigerant from said evaporator and supplying the same with refrigerant liquid, and a secondary volatile refrigerant circuit including a secondary condenser in heat-transfer relation with said primary evaporator, a secondary evaporator for cooling at least a portion of said chamber, and a quantity of volatile refrigerant in said secondary system, the combination with said refrigerator of means responsive to the temperature of the refrigerant vapor compressed by said compressing apparatus to increase the quantity of refrigerant circulating in said secondary circuit when the temperature of said vapor increases and to decrease said quantity when said temperature decreases, the quantity of refrigerant in said circuit being such that said increase and decrease respectively increases and decreases the effectiveness of the secondary evaporator.

MILTON KALISCHIB. 

